Article
Physics, Multidisciplinary
Satoshi Okamoto, Narayan Mohanta, Elbio Dagotto, D. N. Sheng
Summary: This study theoretically demonstrates the interplay between nontrivial band topology and electronic interaction in a multiorbital system on a kagome lattice. Specifically, it is shown that the multiorbital kagome model with atomic spin-orbit coupling naturally supports topological bands characterized by nonzero Chern numbers, and can induce a fractional Chern insulating state when a flat band is 1/3 filled. Possible realization of these findings in real kagome materials is also discussed.
COMMUNICATIONS PHYSICS
(2022)
Article
Materials Science, Multidisciplinary
Eric Bobrow, Junjia Zhang, Yi Li
Summary: By connecting Hund's physics with flat band physics, an exact result for studying ferromagnetism in a multiorbital system is established. The system, consisting of a two-layer model with a p(x), p(y)-orbital honeycomb lattice layer and an f-orbital triangular lattice layer, features a flat band that allows for a percolation representation with an appropriate chemical potential difference between the layers. A paramagnetic-ferromagnetic transition is observed as the ground states become dominated by states with a large maximum-spin cluster when the band approaches half filling, as shown through Monte Carlo simulation.
Article
Physics, Multidisciplinary
Jing Liu, Qing-Wei Wang, Liang-Jian Zou
Summary: This theoretical study investigates superconductivity in multiorbital superconductors based on a three-orbital tight-binding model, revealing a two-dome structure in the T-c-n phase diagram. The competition between different orbital pairings leads to the presence of two superconducting domes, with the boundary of each dome significantly affected by the matrix elements of J(1) and J(2).
Article
Materials Science, Multidisciplinary
Niels Henrik Aase, Asle Sudbo
Summary: This study investigates how spin fluctuations can induce superconductivity in a strongly correlated non-Fermi liquid with repulsive electronic interactions. By using a multichannel Luttinger liquid approach, the researchers find that spin-polarized triplet superconducting correlations persist in the system with sufficiently large interchain couplings.
Article
Physics, Multidisciplinary
A. Sherman
Summary: In this study, the extended Hubbard model on a two-dimensional square lattice at half-filling is investigated using the strong coupling diagram technique. The first-order phase transition in the charge subsystem is found to occur at v = v(c) greater than or similar to U/4. The transition is characterized by an abrupt sign change in the zero-frequency charge susceptibility at the corner of the Brillouin zone. The alternating deviations of electron occupations from the mean value on neighboring sites have short-range order due to fluctuations.
Article
Materials Science, Multidisciplinary
Weiting Chen, Hanqin Ding, Jun Zhang
Summary: In this study, we analytically investigate the phase diagram of a one-dimensional half-filled extended Hubbard model with nearest neighboring four-electron interaction in the weak-coupling regime. Our results show that the additional four-electron coupling splits independent Gaussian and spin-gap transitions and also leads to the charge-gap transition.
RESULTS IN PHYSICS
(2022)
Article
Physics, Multidisciplinary
A. Sherman
Summary: In this study, the extended Hubbard model on a two-dimensional square lattice is investigated using the strong coupling diagram technique. The phase diagrams for different parameters are obtained, showing the charge distribution and magnetic behavior, and revealing the manifestation of the Pomeranchuk effect.
Article
Physics, Multidisciplinary
Udit Khanna, Yuval Gefen, Ora Entin-Wohlman, Amnon Aharony
Summary: Research has found that two-dimensional topological insulators can generate gapless edge modes at the edge, which may lead to finite conductivity. Additionally, it has been discovered that incompressible stripes exhibit broken translational invariance at integer fillings.
PHYSICAL REVIEW LETTERS
(2022)
Article
Multidisciplinary Sciences
Andrew Hardy, Arijit Haldar, Arun Paramekanti
Summary: We propose and study a two-orbital lattice extension of the Sachdev-Ye-Kitaev model in the large-N limit. The phase diagram of this model features a high-temperature isotropic non-Fermi liquid which undergoes first-order thermal transition into a nematic insulator or continuous thermal transition into a nematic metal phase, separated by a tunable tricritical point. These phases arise from spontaneous partial orbital polarization of the multiorbital non-Fermi liquid. We explore the spectral and transport properties of this model, including d.c. elastoresistivity, which exhibits a peak near nematic transition, as well as nonzero frequency elastoconductivity. Our work offers a useful perspective on nematic phases and transport in correlated multiorbital systems.
PROCEEDINGS OF THE NATIONAL ACADEMY OF SCIENCES OF THE UNITED STATES OF AMERICA
(2023)
Article
Materials Science, Multidisciplinary
Liliana Arrachea
Summary: This study discusses the characteristics of Yu-Shiba-Rusinov states in clusters of impurities with classical magnetic moments in a superconducting substrate with s-wave symmetry, considering the effects of multiorbital structure of the impurities and crystal field splitting. The exact solution of the problem and calculation of subgap Green's function were carried out to analyze the subgap excitations spectrum and spectral density for impurities in dimer configurations with different magnetic moments orientations. The application of the same formalism in solving a trimer with frustration in magnetic moments orientation was also illustrated.
Article
Multidisciplinary Sciences
S. Khim, J. F. Landaeta, J. Banda, N. Bannor, M. Brando, P. M. R. Brydon, D. Hafner, R. Kuechler, R. Cardoso-Gil, U. Stockert, A. P. Mackenzie, D. F. Agterberg, C. Geibel, E. Hassinger
Summary: Materials with multiple superconducting phases are rare, but CeRh2As2 has been discovered to exhibit two-phase unconventional superconductivity. The high critical field of 14 tesla in its high-field phase, combined with a transition between different superconducting phases in a c-axis magnetic field, is likely related to the local inversion-symmetry breaking and staggered Rashba coupling introduced at the cerium sites.
Article
Physics, Multidisciplinary
Rahul Soni, Nitin Kaushal, Cengiz Sen, Fernando A. Reboredo, Adriana Moreo, Elbio Dagotto
Summary: In this study, a multi-orbital Hubbard model with two and three orbitals per site was studied using full exact diagonalization. The results were mapped into Heisenberg models at intermediate and large onsite repulsion U. The study provides an estimate for the ratios J(2)/J(1) and J(3)/J(1) in these effective models, showing that they are rather limited and can be enhanced in the intermediate Hubbard U regime.
NEW JOURNAL OF PHYSICS
(2022)
Article
Materials Science, Multidisciplinary
Gao-Wei Qiu, Yi Zhou
Summary: Under the influence of a magnetic field, two weakly linked superconducting ultrathin films exhibit different superconducting states, with one characterized by staggered supercurrent loops and a superfluid density wave, and the other by uniform superfluid density. The phase transition between these two states falls within a specific universality class.
Article
Physics, Multidisciplinary
Yiqing Zhou, D. N. Sheng, Eun-Ah Kim
Summary: Moire systems are important platforms for studying strong correlation physics. Recent experiments on heterobilayer transition metal dichalcogenide Moire systems have revealed a relatively simple model system of an extended Hubbard model on a triangular lattice. Using the density matrix renormalization group, we explored the phase space of the extended Hubbard model on the triangular lattice and found competition between different phases.
PHYSICAL REVIEW LETTERS
(2022)
Article
Physics, Multidisciplinary
Minghu Pan, Xin Zhang, Yinong Zhou, Pengdong Wang, Qi Bian, Hang Liu, Xingyue Wang, Xiaoyin Li, Aixi Chen, Xiaoxu Lei, Shaojian Li, Zhengwang Cheng, Zhibin Shao, Haoxuan Ding, Jianzhi Gao, Fangsen Li, Feng Liu
Summary: In this study, we report the surface growth of a self-assembled monolayer of 2D hydrogen-bond organic frameworks (HOFs) on an Au(111) substrate and the observation of flat bands (FBs). The highly ordered THPB HOF domains and the FB over the whole Brillouin zone were observed through high-resolution scanning tunneling microscopy or spectroscopy and angle-resolved photoemission spectroscopy, respectively. Density functional theory calculations and analyses showed that the observed FB arises from a hidden electronic breathing-kagome lattice without atomically breathing bonds.
PHYSICAL REVIEW LETTERS
(2023)
Article
Physics, Multidisciplinary
Seiichiro Onari, Hiroshi Kontani
Summary: The nematic state with C3 symmetry breaking is observed in magic-angle twisted bilayer graphene (MATBG), which is caused by the modulation of correlated hopping integrals due to E-symmetry particle hole pairing condensation. The nematicity in MATBG originates from prominent quantum interference among SU(4) valley + spin composite fluctuations. This interference mechanism also leads to time-reversal-symmetry-broken valley polarization accompanied by a charge loop current.
PHYSICAL REVIEW LETTERS
(2022)
Article
Multidisciplinary Sciences
Rina Tazai, Youichi Yamakawa, Seiichiro Onari, Hiroshi Kontani
Summary: This article investigates exotic quantum phase transitions in metals and specifically explores the unconventional density-wave order in geometrically frustrated kagome metals and its relationship with superconductivity. The study reveals that the density wave in kagome metals is a bond order, and the significant intersite attraction is caused by quantum interference among paramagnons. Additionally, moderate bond order fluctuations mediate sizable pairing glue, resulting in both singlet s-wave and triplet p-wave superconductivity. The article also provides an explanation for characteristic pressure-induced phase transitions in CsV3Cb5.
Article
Chemistry, Multidisciplinary
Kihyung Sim, Takuya Nakao, Masato Sasase, Soshi Iimura, Junghwan Kim, Hideo Hosono
Summary: The study reveals that using an interlayer in organic-inorganic hybrid perovskite light-emitting diodes (PeLEDs) can suppress the chemical reaction between the metal oxide and hybrid perovskite layers, but it also hinders charge injection into the emission layer. However, by using an 18C6 additive, the chemical reaction can be fully suppressed and high EL performance and outstanding device stability can be achieved simultaneously.
Article
Physics, Multidisciplinary
Seiichiro Onari, Hiroshi Kontani
Summary: This study investigates the formation of various nematic/smectic orders in Fe-based superconductors through a quantum interference mechanism, demonstrating that the diversity of these orders is determined by the characteristics and topology of the Fermi surface of each compound.
FRONTIERS IN PHYSICS
(2022)
Article
Chemistry, Inorganic & Nuclear
Soshi Iimura, Takashi Sasaki, Kota Hanzawa, Satoru Matsuishi, Hideo Hosono
Summary: Using high pressure synthesis, we synthesized a new analogue of iron-based superconductors LaFePH and new oxyhydrides LaFePO1-xHx. No superconducting, magnetic or structural transitions were observed in LaFePO1-xHx except the known superconducting transition at x = 0. DFT calculations reveal that hydride ion substitution raises the Fermi level and leads to a partial electron transfer from Fe-3d to La-5d, explaining the absence of magnetism in LaFePH.
JOURNAL OF SOLID STATE CHEMISTRY
(2022)
Article
Chemistry, Multidisciplinary
Junjie Wang, Tianping Ying, Jun Deng, Cuiying Pei, Tongxu Yu, Xu Chen, Yimin Wan, Mingzhang Yang, Weiyi Dai, Dongliang Yang, Yanchun Li, Shiyan Li, Soshi Iimura, Shixuan Du, Hideo Hosono, Yanpeng Qi, Jian-gang Guo
Summary: Searching for functional square lattices in layered superconductor systems provides a clue to modify electron behavior and find exotic properties. Structural transformation of trigonal SnAs3 to square SnAs4 under pressure enables the realization of a functional As square lattice in Li0.6Sn2As2 and NaSnAs, resulting in record-high Tc values. The transfer of the conductive channel from out-of-plane to in-plane orbitals facilitates electron hopping within the 2D lattice and enhances superconductivity. Reorienting p-orbitals through a local structure transformation offers an effective strategy for modifying layered superconducting systems.
ANGEWANDTE CHEMIE-INTERNATIONAL EDITION
(2023)
Article
Chemistry, Multidisciplinary
Tomoyuki Yamasaki, Soshi Iimura, Junghwan Kim, Hideo Hosono
Summary: In this study, the energy level of 1s-electrons in H- accommodated in solid lanthanum hydrides was evaluated using photoemission measurements and density functional theory calculations. The results showed the existence of a shallow valance band maximum with an ionization potential of 3.8 eV in LaH3, which was mainly attributed to the small electronegativity of hydrogen and the bonding-antibonding interaction between neighboring H(-)s with a close separation. These findings provide insights into the challenge for p-type conduction in hydride semiconductors and the chemical understanding of polyhydride superconductors.
JOURNAL OF THE AMERICAN CHEMICAL SOCIETY
(2023)
Article
Multidisciplinary Sciences
Christopher John Butler, Yuhki Kohsaka, Youichi Yamakawa, Mohammad Saeed Bahramy, Seiichiro Onari, Hiroshi Kontani, Tetsuo Hanaguri, Shinichi Shamoto
Summary: In BaNiS2, correlated-electron behavior, namely electronic nematicity, has been observed using scanning tunneling microscopy. The striped patterns in real space are believed to stem from a lifting of degeneracy among electron pockets at the Brillouin zone boundary. A momentum-dependent energy shift with d-form factor suggests an unusual mechanism driving the nematic instability, which is different from conventional Fermi surface perturbations.
PROCEEDINGS OF THE NATIONAL ACADEMY OF SCIENCES OF THE UNITED STATES OF AMERICA
(2022)
Article
Materials Science, Multidisciplinary
Kota Hanzawa, Jumpei Matsumoto, Soshi Iimura, Yoshimitsu Kohama, Hidenori Hiramatsu, Hideo Hosono
Summary: The electronic transport properties of a highly hydrogen-substituted SmFeAsO epitaxial film with high critical-temperature were investigated under high magnetic fields. The results showed that the film had high potential for superconducting electromagnets and cables due to its high critical temperature, high critical current density, and small anisotropic parameter.
PHYSICAL REVIEW MATERIALS
(2022)
Article
Physics, Multidisciplinary
Zhongyu Yu, Koya Nakamura, Kazuya Inomata, Xiaoling Shen, Taketora Mikuri, Kohei Matsuura, Yuta Mizukami, Shigeru Kasahara, Yuji Matsuda, Takasada Shibauchi, Yoshiya Uwatoko, Naoki Fujiwara
Summary: The study of FeSe has led to the discovery of spin fluctuations originating from Bogoliubov Fermi surfaces in the superconducting state.
COMMUNICATIONS PHYSICS
(2023)
Article
Materials Science, Multidisciplinary
Rina Tazai, Shun Matsubara, Youichi Yamakawa, Seiichiro Onari, Hiroshi Kontani
Summary: Unconventional symmetry breaking due to nonlocal order parameters has attracted considerable attention in many strongly correlated metals. To overcome the difficulty of theoretical foundation, the form factor is introduced to generalize the nonlocal order parameter into the Luttinger-Ward Fermi liquid theory. The established formalism of the density-wave equation can give the thermodynamically stable form factor and calculate various thermodynamic properties.
